Automated packaging devices are often used in high volume production facilities to prepare products for sale and shipment. One common automated packing device is a packaging machine, which divides up the product and drops it into a box or case. The packaging machine typically consist of five sections; a product infeed section, a case feed section, a lift table section, a grid table section and an operator interface section.
The product infeed section of the packaging machine includes a conveyor belt that transfers the product from an up stream process such as filling or labeling, in a serial fashion. The conveyor belt urges the product into grid lanes that align the product into a plurality of rows. Distribution of the product between the grid lanes is accomplished using the force of the conveyor belt and the force created between the individual product items to distribute the product between fixed, stainless steel lane guides. As the product passes between the lane guides, it rests on support strips positioned below the product. At the end of each grid lane is a separation bar, which stops the first product to enter the grid lane. The product is monitored using electronic sensors as it is fed into a grid lane. When the grid lane is filled with the desired amount of product, a brake is applied to stop the serial flow of product in the conveyor belt and, thereby, prevent further product from entering the lane guides.
While the infeed section fills the grid with product, the case feed section delivers empty boxes or cases onto the lift table via a conveyor. The lift table section lifts the cases to a point beneath the grid lanes and waits for product to enter the case before descending. The lift table section is equipped with an air or oil lift table that prompts the up and down motion of the table. As the grid area is filled with product the lift table rises. Once the product is placed in the case, the lift table lowers. The case feed section then discharges the filled case, and an empty case enters the lift table. The operation will then repeat, depending on the number of products in the infeed section.
The grid section is responsible for releasing the product into the empty cases on the lift table. The grid section accomplishes the release of the product using two primary components: the support strip on which the product rests as it enters the grid area, and a grid basket, which guides the product into the case. Once the grid lanes are filled with product, the support strips are shifted to the side allowing the product to fall through the grid basket into the case or box. The support strips are then returned to their original position and the line brake is released allowing subsequent product to be moved from the product infeed into the grid.
An operator interface section controls the system and allows the operator to manage the operation of the machine. Typically, the interface is mounted on a swing boom that enables the operator to control the machine from either side to facilitate viewing of the process. This interface consists of a series of pushbuttons, which enable the operator to start, stop, or alter the performance of the machine, and locate/correct any fault conditions.
As discussed above, the line brake is applied to the infeed conveyor to prevent over filling of the lanes. The application of the brake causes the upstream product to compress together. This compression of the product is known as “line pressure”. Also, as discussed above, the product infeed section divides the product into grid lanes using the force of the conveyor belt and the force created between individual product items. As the product is forced into the grid lanes, the first product to enter the grid lane is forced against the separation bar, and the subsequent products are forced against the first product and against each other. This pressure between the products in the grid lane is known as “wind up”. Despite that line pressure and wind-up cause problems in the packaging operation, they are often used to help move the product in to the grid lanes. Therefore, there is a delicate balance that must be achieved to use line pressure and wind-up without causing problems in the process.
Line pressure results in two main problems in the packaging operation. The first depends on the product being packaged. If the product is made of a glass or plastic oval shape base that has a thinner wall towards the front and back of the base and a thicker wall in the center of the base, excess line pressure may cause the product to break or deform causing delays in the operation as the damaged product is removed and the line is cleared. The second problem occurs with products having irregularly shaped containers (i.e. containers not shaped as a cylinder or parallel-piped). Because the containers are irregularly shaped, contact of containers against each other may cause tipping of adjacent containers resulting in interlocking, tipping, or mispackaging of the product, which again causes delays. To overcome the problems associated with packaging irregularly shaped products, prior art devices used additional devices such as an inflatable membrane to hold the product and prevent it from tipping.
Wind-up tends to cause problems in the packaging lanes. Most cases have product dividers or partitions that protect the product during shipment. Since the product within the lane is in a wound-up state, a gap must be created between the products before they pass into the case. Prior art packaging machines used a separation bar located on the end of the lane to release the wind-up. Once the lane is filled, the separation bar moves away from the row of product, releasing the wind-up. Unfortunately, this technique does not always work well with irregularly shaped products since the wind-up may cause the products to interlock or tip within the grid lanes.
Accordingly, it is considered to be advantageous to have a packaging machine with an infeed section that is able to deliver product into the grid lanes without the problems associated with line pressure or wind-up. It is also advantageous to have a packaging machine capable of continuously filling grid lanes without the use of a line brake. It is also considered advantageous to have a packaging machine capable of continuously filling grid lanes where the products are packaged on a first-in, first-out basis. It is also considered advantageous to provide a packaging machine capable of continuously packaging cases containing variety packs.